LTC3728L Datasheet | Linear Technology

Features n Dual, 180° Phased Controllers Reduce Required Input Capacitance and Power Supply Induced Noise n OPTI-LOOP® pensation Minimizes COUT n ±1% Output Voltage Accuracy (LTC3728LC) n Power Good Output Voltage Indicator n Phase-Lockable Fixed Frequency 250k Hz to 550k Hz n Dual N-Channel MOSFET Synchronous Drive n Wide VIN Range: 4.5V to 28V Operation n Very Low Dropout Operation: 99% Duty Cycle n Adjustable Soft-Start Current Ramping n Foldback Output Current Limiting n Latched Short-Circuit Shutdown with Defeat Option n Output Overvoltage Protection n Low Shutdown IQ: 20µA n 5V and 3.3V Standby Regulators n 3 Selectable Operating Modes: Constant-Frequency, Burst Mode® Operation and PWM n 5mm × 5mm QFN and 28-Lead Narrow SSOP Packages Applications n Notebook and Palmtop puters n Tele Systems n Portable Instruments n Battery-Operated Digital Devices n DC Power Distribution Systems LTC3728L/LTC3728LX Dual, 550k Hz, 2-Phase Synchronous Regulators Description The LTC®3728L/LTC3728LX are dual high performance step-down switching regulator controllers that drive all N‑channel synchronous power MOSFET stages. A constantfrequency, current mode architecture allows phase-lockable frequency of up to 550k Hz. Power loss and noise due to the ESR of the input capacitors are minimized by operating the two controller output stages out of phase. OPTI-LOOP pensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The precision 0.8V reference and power good output indicator are patible with future microprocessor generations, and a wide 4.5V to 28V (30V maximum) input supply range enpasses all battery chemistries. A RUN/SS pin for each controller provides both softstart and optional timed, short-circuit shutdown. Current foldback limits MOSFET dissipation during short-circuit conditions when overcurrent latchoff is disabled. Output overvoltage protection circuitry latches on the bottom MOSFET until VOUT returns...